Page History: Auditory Stimuli
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Page Revision: 2012/05/22 10:21
EventIDE provide multiple approaches for presenting auditory stimuli depending on used audio format and required timing accuracy.
Selecting element for delivering auditory stimuli
There are five
elements in EventIDE that can deliver audio in experiments.
Wave Player Element
- Wave Player is a default element for delivering audio stimuli stored in the raw Wave format. The element is simple to use and it can used to make a stimulus set. The element is recommended as a standard choice because it provide the best time accuracy and fidelity of audio playback. The element supports a choice of multiple sound cards allows to select the sound playback API among four different sound playback APIs available in Windows system.
- Direct Sound element is similar to Wave Player element in functions but it's designed to work exclusively with Direct Sound API. However, the Direct Sound element allows more advanced control of the sound hardware settings. The element can be recommended in Windows XP systems with old-fashion sound cards.
- Audio Player is a general-purpose audio player that supports a wide range of audio formats, including mp3. The element is not recommended when high temporal accuracy is required but could be a natural choice for delivering auditory feedback ans so on.
- Beeper element provides an interface to a hardware tone generator, called PC speaker. If it's sufficient to use auditory stimuli made of simple tones, the element can produce extremely time-accurate sound output.
- Brazen Head element is capable of synthesizing an input test to a speech. Playback timing accuracy can be quite poor due to underlying speech synthesis.
All audio elements in EventIDE can be used in parallel, including multiple instances of the same type.
You can use this element to deliver rich auditory stimuli in experimental scenarios where accurate timing is important and a playback process need to be controlled. For simplest sound tones you can get even better good temporal precision if you use the Beeper element. Alternatively, in scenarios where temporal precision is not necessary, for example: for a post-stimulus voice feedback, you can use the Audio Player element that supports the widest range of sound formats.
You can use this element to deliver rich auditory stimuli in experimental scenarios where very accurate timing is important. For the comparable temporal accuracy but better control on a playback process, use
DirectSound element. For simplest sound tones you can get even better temporal precision if you use the
Beeper element. Alternatively, in scenarios where temporal precision is not necessary, for example for a post-stimulus voice feedback, you can use the Audio Player element that supports the widest range of sound formats.
The ASIO element has few properties for tuning of the sound hardware (other settings are typically available via ASIO driver software). By element, the clip mixing can be switched on and off, and, with monitoring turn on, a basic playback statistics can be measured, like a real startup latency and actual playback duration at runtime. These settings affect the playback performance and, it's always a good idea to test the real playback empirically, with the current hardware, drivers and audio clips.
The element can be used even with sound hardware that does not support ASIO protocol directly. For this purpose you can download and install one of the WDM to ASIO drivers, available for Windows (e.g.
ASIO4ALL driver). However, in this case, the temporal accuracy of playback is normally quite poor.